The present invention relates to a conveyor belt of the type described in WO 89/05765, filed on the 18th of Nov. 1988 by Lennart Tingskog, and in corresponding U.S. Pat. application Ser. No. 07/488055, now U.S. Pat. No. 5,060,787 issued Oct. 29, 1991, which is incorporated herein by reference.
Such a conveyor belt more specifically comprises a flat center piece which is flexurally rigid about the longitudinal axis of the belt owing to a transverse reinforcement and is but slightly extendible in the longitudinal direction owing to a longitudinal reinforcement; two flat edge pieces which are each articulated to one side edge of the center piece, are flexurally rigid about the longitudinal axis of the belt owing to a transverse reinforcement, are extendible in the longitudinal direction of the belt, and together have a width at least equal to the width of the center piece; and two link pieces which connect each edge piece to the center piece, are flexible about the longitudinal axis of the belt and extendible in the longitudinal direction of the belt, are resilient to enable outward pivotal or folding movement of the edge pieces from a position in which they are folded over the center piece, and have a width substantially smaller than that of the center piece.
This type of conveyor belt is advantageous by enabling a closed conveyance of goods, belt paths with tight horizontal and vertical bends and, consequently, horizontal, inclined and even vertical belt path portions, as well as loading and unloading at optional points along the conveying path. This conveyor belt is, in addition, of simple construction and comparatively inexpensive to manufacture, but nevertheless has a long service life even under severe operating conditions.
A conveyor with such a conveyor belt can have a compact design and does not require any complicated support, guide or driving rollers. Such a conveyor is exceptionally versatile, is environment-friendly and involves low production, operation and maintenance costs.
With a conveyor belt of the above type, there may, however, occur sealing difficulties along horizontal curves and steeply inclined or vertical path portions when conveying some types of goods, especially materials having a low internal friction, such as cement.